Originally Posted by theMan-Bat
Superman comics sold bigger in the '50s with the success of the Adventures of Superman television show starring George Reeves. Julius Schwartz and Carmine Infantino boosted the Batman sales with the new look in 1964 and the '60s Batmania hit with the success of the television show starring Adam West and Burt Ward in 1966, which boosted the sales of Batman comics enormously into the bigger seller, outselling Superman.
That only works if you compare one magazine, Batman, to another, Superman for a 2-year period, 1966-1967. Even ignoring that Batman was often bi-monthly for a portion of that period and was frequently just a reprint title. The Superman family of titles vastly outsold the Batman family of titles every year of the 1960s, even during the height of Batmania. Batman and Detective combined didn't outsell Superboy and Superman combined at any point in the 1960s. Without even adding in Action, Lois Lane, Jimmy Olsen, and Adventure Comics which all outsold Detective Comics.
Think about that. Even during the heights of Batmania, Superman dominated the market. Batman didn't really become the dominant sales force he's become until post-Dark Knight Returns/Year One. Even then, Burton's movie provided the real boost.